The invention concerns a nuclear reactor, particularly a pressurized-water reactor, with a reactor pressure vessel, into which lines for feeding-in an emergency core coolant lead. Heretofore, the lines for the emergency coolant realized in actual practice, used to end at the pipelines or connecting stubs of the main coolant loop for the normal coolant. Therefore, they did not lead directly into the reactor pressure vessel. The reason for this appears to have been that nuclear engineers wanted to avoid the otherwise required, additional breakthroughs of the reactor pressure vessel wall, which increase the cost of the reactor pressure vessel, without apparently having any advantage over the practice actually used.